Download-manuals-surface water-manual-sw-volume6fieldmanualwqsampling

Government of India & Government of The Netherlands
DHV CONSULTANTS &
DELFT HYDRAULICS with
HALCROW, TAHAL, CES,
ORG & JPS
VOLUME 6
WATER QUALITY SAMPLING
FIELD MANUAL

Field Manual - Water Quality Sampling (SW) Volume 6
Water Quality Sampling January 2003 Page i
Table of Contents
1 LABORATORY PREPARATIONS FOR SAMPLING 1-1
1.1 SAMPLERS 1-1
1.2 SAMPLE CONTAINERS 1-1
1.3 REAGENT SOLUTIONS 1-3
1.4 INSTRUMENTS 1-3
2 CHECK LIST FOR FIELD VISIT 2-1
3 COLLECTING THE SAMPLE 3-1
3.1 SAMPLE CONTAINERS 3-1
3.2 COLLECTING THE SAMPLE 3-1
3.3 SPECIAL SAMPLES 3-3
3.4 SAMPLE IDENTIFICATION FORMS 3-4
3.5 SAMPLE LABELLING 3-6
3.6 SAMPLE PRESERVATION AND TRANSPORT 3-6
4 STANDARD ANALYTICAL PROCEDURES – FIELD DETERMINATIONS 4-1
4.1 GENERAL 4-1
4.2 COLOUR 4-1
4.3 ODOUR 4-1
4.4 TEMPERATURE 4-2
4.5 ELECTRICAL CONDUCTIVITY 4-2
4.6 pH 4-4
4.7 DISSOLVED OXYGEN 4-4
5 GUIDELINES ON STANDARD ANALYTICAL PROCEDURES 5-1
ODOUR 5-2
TEMPERATURE 5-3
ELECTRICAL CONDUCTIVITY 5-4
pH 5-7
DISSOLVED OXYGEN 5-9

Water Quality Sampling January 2003 Page 1-1
1 LABORATORY PREPARATIONS FOR SAMPLING
Many preparations for a sampling campaign need to be made at the laboratory where the bulk of the
analyses are being carried out, i.e. Level II/II+ laboratory. In some cases, these preparations can be
done at a Level I laboratory, if samples are only being collected for analysis of the 'field parameters'.
Laboratory preparations must be made for:
• Sampler(s)
• Sample containers
• Reagent solutions
• Instruments
• Ice box
1.1 SAMPLERS
At least two types of samplers will be needed in the field: general purpose sampler and Dissolved
Oxygen sampler. The samplers should be cleaned and rinsed. Samplers should also be briefly
checked for functioning, closing caps if applicable, and condition of the rope.
1.2 SAMPLE CONTAINERS
The sample containers for the water quality sampling need to be prepared in the laboratory and given
to the person conducting sampling.
The number of containers and the type of containers needed for the water quality sampling needs to
be determined based on the number of sites to sample and the parameters selected for monitoring. In
the design-phase of the monitoring programme, the sampling locations, and the type of sampling
location (baseline, trend, surveillance, etc.) is determined, which gives the frequency of sampling and
the parameters.
In order to cover the range of parameters which need to be sampled and analysed, a variety of
sample containers are used. Table 1.1 gives the required type of container and the suggested volume
of sample for most common parameters.
Bottles which are to be used for the samples must be thoroughly washed and then rinsed with distilled
water before use. Bottles which are to be used for microbiological samples must be thoroughly
washed and sterilised before use. Sterilising can be carried out by placing the bottles in an autoclave
at 121o
C for fifteen minutes or, if the caps of the bottles do not contain plastic or rubber materials, in
an oven at 170o
C for at least two hours. Bottles to be used for pesticides samples are to be rinsed
with organic solvent (e.g. hexane) prior to use. This should be done in the laboratory.
All bottles should be checked to see if the (screw)caps and seals close properly. Labels for the
sample bottles should be prepared or special pens for labelling the bottles should be used. Making a
list of sample containers per site will ensure that the right number and type of containers are brought
to the field. Always bring a few extra in case of unforeseen events.

Parameter Group Parameter Sample Container
(See note below)
Sample Pre-treatment
(See note below)
General Temperature On-site analysis On-site analysis
Suspended Solids 1 None*
Conductivity On-site analysis On-site analysis
pH On-site analysis On-site analysis
Dissolved Oxygen 2 7
Dissolved Solids 1 None*
Nutrients Ammoniacal Nitrogen 3 8
Total Oxidised Nitrogen 3 8
Total Phosphorus 4 None*
Organic Matter Chemical Oxygen Demand 3 8
Biochemical Oxygen Demand 2 4
o
C, Dark
Major Ions Sodium 3 None*
Potassium 3 None*
Calcium 3 None*
Magnesium 3 None*
Carbonates and Bicarbonates 1 None*
Chloride 1 None*
Sulphate 1 None*
Other Inorganics Silica 1 None*
Fluoride 1 None*
Boron 1 None*
Metals Cadmium 3 9
Mercury 4 9
Zinc 3 9
Organics Pesticide (Indicator) 5 4
o
C, Dark
Synthetic Detergents 1 None*
Organic Solvents 1 4
o
C, Dark
Phenols 5 8
Microbiological Total coliforms 6 4
o
C, Dark
Biological Chlorophyll ‘a’ 1 4
o
C, Dark
NOTES:
Containers:
1. 1000 millilitre polyethylene bottle
2. Special BOD bottle (normally 300 millilitre)
3. 500 millilitre polyethylene bottle
4. 100 millilitre glass bottle
5. 1000 millilitre glass (or Teflon) bottle with Teflon lined caps
6. Strong thick-walled, screw-capped glass bottle (300 millilitre capacity). Only good quality will maintain a good seal after
multiple sterilisations in an autoclave
Preservation:
7. Samples for dissolved oxygen analysis are fixed by adding 1 ml of manganous sulphate solution, 1 ml of alkaline
iodide-azide solution and mixing. Care should be taken to ensure that no air is added to the sample during this process.
8. Samples should be acidified with 2 ml of concentrated sulphuric acid
9. Samples should be acidified with 2 ml of concentrated nitric acid.
*None: Ideally, all samples should be kept cool and in the dark after collection. If this is not possible, then at least
samples for BOD, coliforms, chlorophyll, pesticides and other organics that are likely to volatilize MUST be kept at 4
o
C,
and dark. Remaining samples can have no preservation.
Table 1.1: Water Quality Parameters - Sampling Containers and Pre-treatments Required

1.3 REAGENT SOLUTIONS
For some of the field analyses, reagent solutions are necessary for the analysis. All necessary
reagent solutions should be prepared in the laboratory and brought to the field by the sample
collector. Alternatively, reagent solutions can be kept at a Level I laboratory near the sampling site, if
the 'field analyses' are going to be made there. In all cases, sample preservatives and DO fixing
solutions must be brought to the field and added to the samples immediately after collection.
Refer to the 'Guidelines on Standard Analytical Procedures for Water Analyses' for detailed
procedures on preparation of reagents. Relevant procedures are given in Chapter 5.
For analysis of pH, buffer solutions are necessary to standardise the pH meter: Buffer solutions
should be prepared in the laboratory, or purchased, for pH = 4, pH = 7, and pH = 9.
For analysis of Electrical Conductivity, standard potassium chloride solution, KCl (0.01M) is needed to
standardise the conductivity meter.
For analysis of dissolved oxygen, DO fixing chemicals are necessary:
• manganous sulphate solution
• alkaline iodide-azide solution
• concentrated sulphuric acid
DO fixing chemicals should be kept in glass or PE bottles. If a glass bottle is used, a rubber stopper
must be used for the alkaline reagent. A glass pipette or dropper of 2 ml capacity is needed to add the
fixing chemicals to the samples.
Chemicals for DO titration must also be brought to the field, or must be available at the Level I
laboratory where the titration will be done:
• Starch indicator
• Standard sodium thiosulphate titrant, 0.025M (0.025N). This needs to be standardised with
potassium bi-iodate solution 0.0021M (0.0126N).
For preservation of certain samples, concentrated nitric acid and concentrated sulfuric acid are
needed.
A supply of distilled water is needed for rinsing equipment.
1.4 INSTRUMENTS
Some instruments and equipment are necessary to make the field analyses. Instruments and
equipment must be brought to the field, or must be available at the Level I laboratory where the 'field
analyses' will be done. Temperature should always be measured in the field:
• For measurement of Temperature, a (mercury) thermometer or thermistor is needed.
• For analysis of Electrical Conductivity, a conductivity meter is needed.
• For analysis of pH, a pH meter is needed.
• For analysis of DO, equipment for a DO titration is necessary: Erlenmeyer flask and burette

Note: it is possible that instead of separate meters for temperature, pH and conductivity, there is a
single instrument with different probes which will measure all three parameters.
A supply of batteries and standard spare parts should also be carried along with the field instruments.

2 CHECK LIST FOR FIELD VISIT
Table 2.1 contains a list of items which should be checked before starting on a sampling mission. At
least one day before sampling, make sure that all the arrangements are made as per the check list.
Make sure that you know how to reach sampling site(s). Take help of location map for each site which
shows the sample collection point with respect to prominent landmarks in the area. In case there is
any deviation in the collection point, record it on the sample identification form giving reason.
Note that depending on the local conditions, water body, analysis requirements, etc., not all items on
the check list may be necessary. Other items, not listed, may be required. The field operation may
make his or her own personal checklist based on Table 2.1.
Decide on the number of each item that would be required depending on the number of samples to be
collected. It is always safer to carry a few numbers in excess.
If for any reason the laboratory conducting analyses is different from the laboratory preparing sample
bottles, ensure that the concerned laboratory is informed of the programme and ready to receive
samples, particularly those which would need immediate attention.
• Itinerary for the trip (route, stations to be
covered, start and return time)
• Personnel and sample transport arrangement
• Area map • Sampling site location map
• Icebox filled with ice or icepacks • Weighted bottle sampler
• DO sampler • Rope
• BOD bottles • Sample containers
• Special sample containers: bacteriological, heavy
metals, etc.
• DO fixing and titration chemicals and glassware
• Sample preservatives (e.g. acid solutions) • Thermometer
• Tissue paper • Other field measurement kit, as required
• Sample identification forms • Labels for sample containers
• Field notebook • Pen / pencil / marker
• Soap and towel • Match box
• Spirit lamp • Torch
• Drinking water • Knife
• Gloves and eye protection
Table 2.1: Checklist for field visit

3 COLLECTING THE SAMPLE
3.1 SAMPLE CONTAINERS
The sample containers needed for a sampling campaign are prepared by the laboratory and given to
the person collecting samples. An overview of the types of containers and preservation is given in
Table 3.1. More detailed information on the specific containers needed for each parameter is given in
Table 1.1.
Analysis Container Volume (mL) Preservation
0 on site analysis PE bowl or container ±200 -
1
General
(SS, TDS, major ions, chlorophyll-a)
Glass, PE 1000 -
2 COD, NH3, NO2-+NO3- Glass, PE 500 H2SO4, pH <2
3 P Glass 100 -
4 DO special BOD bottle 300 DO fixing
5 BOD Glass, PE 1000 4
o
C, Dark
6 Coliforms Glass, PE, Sterilised 300 4
o
C, Dark
7 Heavy metals (Cd, Zn) Glass, PE 500 HNO3, pH <2
8 Mercury Glass 1000 HNO3, pH <2
9 Pesticides Glass, Teflon 1000 4
o
C, Dark
Table 3.1: Container types and volumes needed for sampling
3.2 COLLECTING THE SAMPLE
Samples will be collected from the selected site at the intended date and time of sampling. At that
time the collector should collect the required volumes of water in the allocated container(s). Usually,
unless specified otherwise, the samples to be collected are grab-samples taken from the well-mixed
section of the main current.
In the event that the monitoring is meant to check the water quality for a specific water use function
(i.e. surveillance monitoring), then the sample should be collected at the point of use. For example, if
water quality monitoring is meant to check bathing water quality, a sample should be collected at the
bathing location. For water quality monitoring to check drinking water quality, a sample should be
collected at the point of water abstraction.
The simplest form of a water sampling device is a bottle or bucket attached to a string. However, this
will not sink easily below the water surface. To lower a plastic or glass bottle in a body of water it is
necessary to use a bracket or holder of sufficient weight to overcome the buoyancy of the bottle and
allow it to sink rapidly to the required depth, usually 20-30 cm below the water surface. Such a holder
designed to contain a one or two-litre bottle is shown in Figure 3.1.

Figure 3.1:
Sample bottle holder for sampling
Where feasible a sample may be collected by holding the sample bottle in hand and submerging it.
Collect the sample from the well-mixed section of the river, approximately 20-30 cm below the water
surface (see Figure 3.2) . Care must be taken not to catch any floating material or bed material into
the container. If the water is less than 40cm, the sample should be collected at half the actual water
depth. If possible, sampling from shallow waters (less than 40cm) should be prevented by moving,
within the site, to a deeper part of the river or stream.
Figure 3.2:
Collecting a sample from surfce water
Samples from reservoir sites will be collected from the outgoing canal, power channel or water intake
structure, in case water is pumped. When there is no discharge in the canal, sample will be collected
from the upstream side of the regulator structure, directly from the reservoir.
Rinse the sample container three times with the sample before it is filled.
Leave a small air space in the bottle to allow mixing of sample at the time of analysis.

3.3 SPECIAL SAMPLES
Dissolved Oxygen
Collecting a sample for Dissolved Oxygen analysis requires special sampling equipment: a purpose-
built dissolved oxygen sampler, for collection of undisturbed samples from surface waters (Figure
3.3). This sampler prevents air bubbles from entering into the sample and changing the dissolved
oxygen concentration of the sample.
To collect the sample, insert the special ground glass-stoppered bottle (a ‘BOD bottle’) into the DO
sampler. Submerge the sampler, such that water enters the BOD bottle directly by means of a dip-
pipe thus displacing all air from the bottle. Retrieve the sampler after it is full, and then immediately
seal the full bottle with a ground glass stopper.
The Dissolved Oxygen sample needs to be 'fixed' immediately after collection as described in Chapter
3.6.
Figure 3.3:
Dissolved oxygen sampler (with one BOD-bottle).
Composite Samples
In most cases, a composite sample is a combination of equal volumes of a number of grab samples
collected at the same location at different times. The volumes of the individual grab samples making
the composite sample may also be varied in proportion to the flow in the river at the time of sampling.
In such a case it is called a flow weighted composite sample.
Composite samples may be required only in special cases for calculation of mass flux in rivers when
the quality of water is suspected to change over short periods of time. It is, however, a routine practice
when wastewater streams are to be characterised.
Air outlet
DO

Integrated Sample
An integrated sample is a mixture of grab samples collected simultaneously at different locations
across the width of the river and/or at different depths. The need for an integrated sample may occur
for very wide and deep rivers where the quality of water may vary across its width and depth.
3.4 SAMPLE IDENTIFICATION FORMS
The sample identification form provides a record of all important information concerning the sample
collected. Complete the sample identification form at each monitoring site, detailing the samples that
are collected at that site. Note that if more than one bottle is filled at a site, for different types of
analyses, this is to be registered on the same form.
Local conditions, such as weather, human activity on the banks, state of water body, etc., at the
sampling site should be recorded on the form, at the time of sampling. Such information may be
useful in analysis of data.
The form for identifying the sample and recording the field measurements and site conditions is given
in Figure 3.4.
Sample identification forms should be given to the laboratory analyst together with the samples. The
forms should all be kept in a master file at the level II or II+ laboratory where the samples are
analysed.

Sample code
Observer Agency Project
Date Time Station code
Container Preservation Treatment
Parameter
Code
Glass PVC PE Teflon None Cool Acid Other None Decant Filter
(1) Gen
(2) Bact
(3) BOD
(4) COD, NH3,NO3
-
(5) H. Metals
(6)Tr. Organics
Source of sample
Waterbody Point Approach Medium Matrix
o River
o Drain
o Canal
o Reservoir
o Main current
o Right bank
o Left bank
O Bridge
O Boat
O Wading
o Water
o Susp matter
o Biotap
o Sediment
o Fresh
o Brackish
o Salt
o Effluent
Sample type o Grab o Time-comp o Flow-comp o Depth-integ o Width-integ
Sample device o Weighted bottle o Pump o Depth sampler
Field determinations
Temp
o
C PH EC µmho/cm DO mg/L
Odour
Code
(1) Odour free
(2) Rotten eggs
(3) Burnt sugar
(4) Soapy
(5) Fishy
(6) Septic
(7) Aromatic
(8) Chlorinous
(9) Alcoholic
(10) Unpleasant
Colour
code
(1) Light brown
(2) Brown
(3) Dark brown
(4) Light green
(5) Green
(6) Dark green
(7) Clear
(8) Other (specify)
Remarks
Weather o Sunny o Cloudy o Rainy o Windy
Water vel. m/s o High (> 0.5) o Medium (0.1-0.5) o Low (< 0.1) o Standing
Water use o None o Cultivation o Bathing & washing o Cattle washing
o Melon/vegetable farming in river bed
Figure 3.4: Sample identification form for surface water samples

3.5 SAMPLE LABELLING
Label the sample container properly, preferably by attaching an appropriately inscribed tag or label.
Alternatively, the bottle can be labelled directly with a water-proof marker. Information on the sample
container or the tag should include:
• sample code number (identifying location)
• date and time of sampling
• source and type of sample
• pre-treatment or preservation carried out on the sample
• any special notes for the analyst
• sampler’s name
3.6 SAMPLE PRESERVATION AND TRANSPORT
Preserve the collected samples as specified in Table 3.1 and Table 1.1.
Samples for BOD and bacteriological analyses should be stored at a temperature below 4o
C and in
the dark as soon as possible after sampling. In the field this usually means placing them in an
insulated cool box together with ice or cold packs. Once in the laboratory, samples should be
transferred as soon as possible to a refrigerator.
Samples for DO measurement should be chemically fixed immediately after collection:
a. With the stopper in the bottle, drain any liquid in the flared lip of the BOD bottle containing the
sample.
b. Remove stopper and add 1 mL of MnSO4 followed by 1 mL alkali-iodide-azide reagent. Hold the
pipette tip just below the liquid surface touching the side of the bottle. Wash the pipette before
returning to the reagent bottles.
c. Stopper the bottle carefully to exclude air bubbles. Mix by inverting the bottle a few times.
d. Allow the brown manganese hydroxide floc (white floc indicates absence of DO) to settle
approximately to half the bottle volume, then add 1.0 mL conc H2SO4 and re-stopper. Mix by
inverting several times until dissolution is complete. Such samples can then be kept up to six
hours before titration.
If samples collected for chemical oxygen demand (COD) analysis cannot be analysed on the day of
collection they should be preserved below pH 2 by addition of concentrated sulphuric acid. This
procedure should also be followed for samples for ammoniacal nitrogen, total oxidised nitrogen and
phenol analysis.
Samples which are to be analysed for the presence of metals, should be acidified to below pH 2 with
concentrated nitric acid. Such samples can then be kept up to six months before they need to be
analysed; mercury determinations should be carried out within five weeks, however.
After labelling and preservation, the samples should be placed in an insulated cool box for
transportation (Figure 3.5). Samples should be transported to concerned laboratory (level II or II+) as
soon as possible, preferably within 48 hours.
Analysis of bacteriological samples should be started and analysed within 24 hours of collection.
If samples are being brought to a Level I laboratory for the 'field determinations', they should be
transported in less than 24 hours.

Figure 3.5: Insulated bottle carrier for water quality samples

4 STANDARD ANALYTICAL PROCEDURES – FIELD
DETERMINATIONS
4.1 GENERAL
Measurements of colour, odour, temperature, electrical conductivity, pH and dissolved oxygen are
considered to be 'Field Determinations' and should be made as soon as possible after collecting a
sample.
Measurement of these parameters can be made in the field if field meters are available. This is the
best option, as the analyses will be made immediately. Another option is to bring samples to the
nearest Level I laboratory, where equipment for analyses is set up. If samples are brought to the level
one laboratory, the travel time should be very short, so that parameter values do not change between
the time the sample is collected at the time of analysis. Note that the DO sample must be 'fixed'
immediately after collection and that the temperature must be measured at the site.
4.2 COLOUR
Determining the colour in the field is relatively easy. Pour an aliquot of approximately 10mL of sample
into a glass test tube and judge the colour observed. Assign one of the colour codes from Table 4.1 to
the sample. In case the colour of water does not fall under code 1 to 7, select code 8 and note down
the details of the colour observed. Report the colour code on the sample identification form.
Colour
Code
(1) Light brown
(2) Brown
(3) Dark brown
(4) Light green
(5) Green
(6) Dark green
(7) Clear
(8) Other specify
Table 4.1: Colour codes for field determination of colour
4.3 ODOUR
Determining the odour should always be done in the field, as soon as possible after collecting a
sample. After collection, fill a cleaned odourless bottle half-full of sample, insert stopper, shake
vigorously for 2-3 seconds and then quickly smell the odour. Alternatively, pour an aliquot of
approximately 5 mL of sample into a glass test tube and judge the odour.
Assign one of the odour codes from Table 4.2 to the sample. In case option 10 'unpleasant' is
selected please try to note down the details of the odour observed (e.g. agreeable or disagreeable).
Note: Do not select option 10 if the odour observed can be classified as one in the list from 1 to 9.
Report the odour code on the sample identification form.

Odour
Code
(1) Odour free
(2) Rotten eggs
(3) Burnt sugar
(4) Soapy
(5) Fishy
(6) Septic
(7) Aromatic
(8) Chlorinous
(9) Alcoholic
(10) Unpleasant
Table 4.2: Odour codes for field determination of odour
4.4 TEMPERATURE
Water temperature should be measured in degrees Celsius, using a mercury thermometer or a
thermistor. Normally, if temperature is measured electronically using a thermistor this device is built
into an instrument which is capable of making other water quality measurements (e.g., pH and EC).
Whenever possible, the temperature should be measured by directly dipping the thermometer in the
natural body of water being studied. In case it is not possible, collect about 500 mL sample in a plastic
or glass container and measure temperature by immersing the thermometer in the sample. Read the
temperature after equilibration (no more change in the temperature reading).
Report the Temperature on the sample identification form in degrees Celsius with 1 figure after the
decimal point e.g. 13.2 o
C.
4.5 ELECTRICAL CONDUCTIVITY
Measurement of Electrical Conductivity should be made in the field at the time of sampling, using a
purpose-built meter. Refer to the 'Guideline on Standard Analytical Procedures for Water Analyses' for
detailed procedures including preparation of reagents - given in Chapter 5. The procedure is also
given below:
a) Prepare the instrument following manufacturer's instructions. Rinse conductivity cell with at
least three portions of 0.01M KCl solution. Measure resistance of a fourth portion and note
temperature.
b) In case the instrument indicates conductivity directly, and has internal temperature
compensation, after rinsing as above, adjust temperature compensation dial to 0.0191/ o
C
and with the probe in standard KCl solution, adjust meter to read 1412 µmho/cm. Continue at
step d.
c) Compute the cell constant, KC according to the formula:
(4.1)
where: KC = the cell constant, 1/cm
CKCl = measured conductance, µmho
t = observed temperature of standard KCl solution, °C
The value of temperature correction [0.0191 x (t-25)+1] can be read from Table 4.3.
( )[ ]125t0.0191
C
1412
K
KCl
C +−×=

d. Rinse cell with one or more portions of sample. The level of sample aliquot must be above the
vent holes in the cell and no air bubbles must be allowed inside the cell. Adjust the temperature of
sample to about 25o
C (outside the temperature range of 20 - 30o
C, error increases as the sample
temperature increasingly deviates from the reporting temperature of 25o
C). Read sample
conductivity and note temperature to nearest 0.1o
C.
e. Thoroughly rinse the cell in distilled water after measurement; keep it in distilled water when not in
use.
Calculation
a. When sample conductivity is measured with instruments having temperature compensation, the
readout automatically is corrected to 25o
C. If the instrument does not have internal temperature
compensation, conductivity at 25o
C is:
Electrical Conductivity (4.2)
where:
KC = the cell constant, 1/cm
CM = measured conductance of the sample, µmho
t = observed temperature of sample, °C
b. Record the meter reading, the unit of measurement and the temperature of the sample at the time
of reading. Report the Electrical Conductivity at 25o
C on the sample identification form in
µmho/cm with no figures after the decimal point, e.g. 1135 µmho/cm.
T (°C) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
15 0.810 0.812 0.814 0.816 0.818 0.820 0.821 0.823 0.825 0.827
16 0.829 0.831 0.833 0.835 0.837 0.839 0.840 0.842 0.844 0.846
17 0.848 0.850 0.852 0.854 0.856 0.858 0.859 0.861 0.863 0.865
18 0.867 0.869 0.871 0.873 0.875 0.877 0.878 0.880 0.882 0.884
19 0.886 0.888 0.890 0.892 0.894 0.896 0.897 0.899 0.901 0.903
20 0.905 0.907 0.909 0.911 0.913 0.915 0.916 0.918 0.920 0.922
21 0.924 0.926 0.928 0.930 0.932 0.934 0.935 0.937 0.939 0.941
22 0.943 0.945 0.947 0.949 0.951 0.953 0.954 0.956 0.958 0.960
23 0.962 0.964 0.966 0.968 0.970 0.972 0.973 0.975 0.977 0.979
24 0.981 0.983 0.985 0.987 0.989 0.991 0.992 0.994 0.996 0.998
25 1.000 1.002 1.004 1.006 1.008 1.010 1.011 1.013 1.015 1.017
26 1.019 1.021 1.023 1.025 1.027 1.029 1.030 1.032 1.034 1.036
27 1.038 1.040 1.042 1.044 1.046 1.048 1.049 1.051 1.053 1.055
28 1.057 1.059 1.061 1.063 1.065 1.067 1.068 1.070 1.072 1.074
29 1.076 1.078 1.080 1.082 1.084 1.086 1.087 1.089 1.091 1.093
30 1.095 1.097 1.099 1.101 1.103 1.105 1.106 1.108 1.110 1.112
31 1.114 1.116 1.118 1.120 1.122 1.124 1.125 1.127 1.129 1.131
32 1.133 1.135 1.137 1.139 1.141 1.143 1.144 1.146 1.148 1.150
33 1.152 1.154 1.156 1.158 1.160 1.162 1.163 1.165 1.167 1.169
Table 4.3: Value of [0.0191 x (t-25)+1] for Temperature Correction of EC Measurement
125)0.0191(t
KC
mhos/cm)( CM
+−
×
=µ

4.6 pH
Measurement of pH should be made in the field at the time of sampling, using a purpose-built meter.
Follow the procedure below:
a. Prepare instrument as according to manufacturer's instructions. Remove instrument electrodes
from storage solution, rinse with distilled water, blot dry with soft tissue.
b. First standardisation: Place electrode in initial buffer solution and standardise pH meter to the
known pH according to manufacturer’s instructions.
c. Second standardisation: Remove electrodes from the first buffer, rinse thoroughly with distilled
water, blot dry and immerse in second buffer preferably of pH within 2 pH units of the pH of the
sample. Read pH of the second buffer, which should be within 0.1 unit of the known pH of the
buffer.
d. Determine pH of the sample using the same procedure as in (c) after establishing equilibrium
between electrodes and sample. For buffered samples this can be done by dipping the electrode
into a portion of the sample for 1 min. Blot dry, immerse in a fresh portion of the same sample,
and read pH.
e. With dilute poorly buffered solutions, equilibrate electrodes by immersing in three or four
successive portions of the sample. Take a fresh sample to measure pH.
f. Stir the sample gently while measuring pH to insure homogeneity.
g. Report the pH on the sample identification form in pH units with 1 figure after the decimal point,
e.g. 7.6.
4.7 DISSOLVED OXYGEN
After the dissolved oxygen sample has been fixed by addition of chemicals (see Chapter 3.6), the
sample is analysed by Winkler titration.
Titrate 201 mL sample with standard Na2S2O3 (thiosulphate) solution to a pale straw colour. Add a few
drops of starch indicator. Continue titration to first disappearance of blue colour. Calculate
concentration of dissolved oxygen as:
(4.3)
where: V = mL thiosulphate solution used
M = molarity of thiosulphate titrant
Report the Dissolved Oxygen concentration on the sample identification form in mg/l with 1 figure after
the decimal point, e.g. 8.2 mg/l.
0.025
MV
DO/Lmg
×
=

5 GUIDELINES ON STANDARD ANALYTICAL PROCEDURES
The 'Guidelines on Standard Analytical Procedures for Water Analyses' for detailed procedures
including preparation of reagents are given here for the following analyses:
• Odour
• Temperature
• Electrical Conductivity
• pH
• Dissolved Oxygen

OD ODOUR
Method: QUALITATIVE HUMAN RECEPTOR
ID: 1.19 Version: 1
Procedure
a. As soon as possible after collection of sample, fill a cleaned odourless bottle half - full of
sample, insert stopper, shake vigorously for 2 to 3 seconds and then quickly observe the
odour. The sample should be at ambient temperature.
b. Report the odour as: odour free, rotten egg, burnt sugar, soapy, fishy, septic, aromatic,
chlorinous, alcoholic odour or any other specific odour. In case it is not possible to specify the
exact nature of odour, report as agreeable or disagreeable.

T TEMPERATURE
Method: MERCURY THERMOMETER
ID: 1.27 Version: 1
Apparatus
Mercury thermometer having a scale marked for every 0.1o
C.
Procedure
a. Immerse thermometer in the sample up-to the mark specified by the manufacturer and read
temperature after equilibration.
b. When a temperature profile at a number of different depths is required a thermistor with a
sufficiently long lead may be used.
Reporting
Report the temperature in units of degree Celsius with 1 figure after the decimal point, e.g. 13.2 °C.

EC ELECTRICAL CONDUCTIVITY
Method: CONDUCTIVITY CELL POTENTIOMETRIC
ID: 1.10 Version: 1
Apparatus
a. Conductivity meter capable of measuring conductivity with an error not exceeding 1% or
0.1mS/m which ever is greater.
b. Conductivity cell, Pt electrode type. For new cells not already coated and old cell giving erratic
readings platinise according to the following procedure. Clean the cell with chromic - sulphuric
acid cleaning mixture. Prepare platinising solution by dissolving 1g chloroplatinic acid, H2Pt
Cl6.6H2O and 12 mg lead acetate in 100 mL distilled water. Immerse electrodes in this
solution and connect both to the negative terminal of a 1.5 V dry cell battery (in some meters
this source is built in). Connect the positive terminal to a platinum wire and dip wire into the
solution. Continue electrolysis until both cell electrodes are coated with platinum black.
Reagent
a. Conductivity water - use distilled water boiled shortly before use to minimise CO2 content.
Electrical conductivity must be less than 0.1 µmho/cm.
b. Standard potassium chloride solution, KCl, 0.01M, conductivity 1412 µmho/cm at 25 o
C.
Dissolve 745.6 mg anhydrous KCl (dried 1 hour at 180 °C) in conductivity water and dilute to
1000 mL. This reference solution is suitable when the cell has a constant between 1 and 2
per cm.
Procedure
a. Rinse conductivity cell with at least three portions of 0.01M KCl solution. Measure resistance
of a fourth portion and note temperature.
b. In case the instrument indicates conductivity directly, and has internal temperature
compensation, after rinsing as above, adjust temperature compensation dial to 0.0191/ °C
and with the probe in standard KCl solution, adjust meter to read 1412 µmho/cm. continue at
step d.
c. Compute the cell constant, KC according to the formula:
CKCl = measured conductance, µmho
t = observed temperature of standard KCl solution, °C
( )[ ]125t0.0191
C
1412
K
KCl
C +−×=

d. Rinse cell with one or more portions of sample. The level of sample aliquot must be above the
vent holes in the cell and no air bubbles must be allowed inside the cell. Adjust the
temperature of sample to about 25°C (outside a temperature range of 20 - 30°C, error
increases as the sample temperature increasingly deviates from the reporting temperature of
25°C). Read sample conductivity and note temperature to nearest 0.1°C.
e. Thoroughly rinse the cell in distilled water after measurement, keep it in distilled water when
not in use.
Calculation
a. When sample conductivity is measured with instruments having temperature compensation,
the readout automatically is corrected to 25 o
C. If the instrument does not have internal
temperature compensation, conductivity at 25 o
C is:
CM = measured conductance of the sample, µmho
t = observed temperature of sample, 0
C
b. Record the meter reading, the unit of measurement and the temperature of the sample at the time
of reading. Report the electrical conductivity at 25°C. Report conductivity preferably in µmho/cm.
Table 5.1: Value of [0.0191 x (T-25) + 1) for Temperature Correction of EC measurement
125)0.0191(t
KC
mhos/cm)(tyConductiviElectrical CM
+−
×
=µ
T (°C) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
15 0.810 0.812 0.814 0.816 0.818 0.820 0.821 0.823 0.825 0.827
16 0.829 0.831 0.833 0.835 0.837 0.839 0.840 0.842 0.844 0.846
17 0.848 0.850 0.852 0.854 0.856 0.858 0.859 0.861 0.863 0.865
18 0.867 0.869 0.871 0.873 0.875 0.877 0.878 0.880 0.882 0.884
19 0.886 0.888 0.890 0.892 0.894 0.896 0.897 0.899 0.901 0.903
20 0.905 0.907 0.909 0.911 0.913 0.915 0.916 0.918 0.920 0.922
21 0.924 0.926 0.928 0.930 0.932 0.934 0.935 0.937 0.939 0.941
22 0.943 0.945 0.947 0.949 0.951 0.953 0.954 0.956 0.958 0.960
23 0.962 0.964 0.966 0.968 0.970 0.972 0.973 0.975 0.977 0.979
24 0.981 0.983 0.985 0.987 0.989 0.991 0.992 0.994 0.996 0.998
25 1.000 1.002 1.004 1.006 1.008 1.010 1.011 1.013 1.015 1.017
26 1.019 1.021 1.023 1.025 1.027 1.029 1.030 1.032 1.034 1.036
27 1.038 1.040 1.042 1.044 1.046 1.048 1.049 1.051 1.053 1.055
28 1.057 1.059 1.061 1.063 1.065 1.067 1.068 1.070 1.072 1.074
29 1.076 1.078 1.080 1.082 1.084 1.086 1.087 1.089 1.091 1.093
30 1.095 1.097 1.099 1.101 1.103 1.105 1.106 1.108 1.110 1.112
31 1.114 1.116 1.118 1.120 1.122 1.124 1.125 1.127 1.129 1.131
32 1.133 1.135 1.137 1.139 1.141 1.143 1.144 1.146 1.148 1.150
33 1.152 1.154 1.156 1.158 1.160 1.162 1.163 1.165 1.167 1.169
34 1.171 1.173 1.175 1.177 1.179 1.181 1.182 1.184 1.186 1.188
35 1.190 1.192 1.194 1.196 1.198 1.200 1.201 1.203 1.205 1.207

Multiply By to obtain
µS/m 0.01 µmho/cm
mS/cm 10 µmho/cm
mS/cm 1000 µmho/cm
µS/cm 1 µmho/cm
mmho/cm 1000 µmho/cm
Table 5.2: Conversion table for units of electrical conductivity
Note
1S = 1mho
Reporting
Report electrical conductivity in units of µmho/cm, with 0 digits after the decimal point, e.g.
1135 µmho/cm. Use Table 5.2 for conversion of units.

pH pH
Method: POTENTIOMETRIC
ID: 1.21 Version: 1
Apparatus
a. pH meter with temperature compensating device, accurate and reproducible to 0.1 pH unit
with a range of 0 to 14.
b. Reference electrode preferably with quartz liquid junction. Follow manufacturer’s instructions
on use and care of the reference electrode. Refill non-sealed electrodes with correct
electrolyte to proper level and make sure junction is properly wetted.
c. Follow manufacturer’s instructions on use and care of electrode.
Reagents
a. Potassium hydrogen phthalate buffer, 0.05M, pH 4.00. Dissolve 10.12 g KHC8H4O4
(potassium hydrogen phthalate) in 1000 mL freshly boiled and cooled distilled water
b. 0.025M Potassium dihydrogen phosphate + 0.025M disodium hydrogen phosphate buffer, pH
6.86. Dissolve 3.387 g KH2PO4 + 3.533 g Na2HPO4 in 1000 mL freshly boiled and cooled
distilled water
c. 0.01M sodium borate decahydrate (borax buffer), pH = 9.18. Dissolve 3.80 g Na2B4O7.10H2O
in 1000 mL freshly boiled and cooled distilled water.
d. Store buffer solutions in polyethylene bottles. Replace buffer solutions every 4 weeks.
Procedure
a. Remove electrodes from storage solution, rinse, blot dry with soft tissue, place in initial buffer
solution and standardise pH meter according to manufacturer’s instructions.
b. Remove electrodes from the first buffer, rinse thoroughly with distilled water, blot dry and
immerse in second buffer preferably of pH within 2 pH units of the pH of the sample. Read
pH, which should be within 0.1 unit of the pH of the second buffer.
c. Determine pH of the sample using the same procedure as in (b) after establishing equilibrium
between electrodes and sample. For buffered samples this can be done by dipping the
electrode into a portion of the sample for 1 min. Blot dry, immerse in a fresh portion of the
same sample, and read pH.
d. With dilute poorly buffered solutions, equilibrate electrodes by immersing in three or four
successive portions of the sample. Take a fresh sample to measure pH.
e. Stir the sample gently while measuring pH to insure homogeneity.

Reporting
Report results in pH units with 1 digit after the decimal point, e.g. 7.6.

DO DISSOLVED OXYGEN
Method: WINKLER AZIDE MODIFICATION TITRIMETRIC
ID: 1.9 Version: 2Approval:
Apparatus
a. DO sampler, for collection of undisturbed samples from surface waters.
b. BOD bottles, 300 mL, narrow mouth, flared lip, with tapered and pointed ground glass
stoppers.
c. A siphon tube, for laboratory use.
Reagents
a. Manganous sulphate solution. Dissolve 480 g MnSO4 .4H2O, 400 g MnSO4.2H2O or 364 g
MnSO4.H2O in distilled water, filter and dilute to IL.
b. Alkali-iodide-azide reagent. Dissolve 500 g NaOH (or 700 g KOH) and 135 g NaI (or 150 g KI)
in distilled water and dilute to IL. Add 10 g NaN3 dissolved in 40 mL distilled water.
c. Sulphuric acid, conc
d. Starch indicator. Dissolve 2 g laboratory grade soluble starch and 0.2 g salicylic acid as a
preservative, in 100 mL hot distilled water.
e. Standard sodium thiosulphate titrant, 0.025M (0.025N). Dissolve 6.205 g Na2S2O3.5H2O in
distilled water. Add 1.5 mL 6NNaOH or 0.4 g solid NaOH and dilute to 1000 mL . Standardise
with bi-iodate solution.
f. Standard potassium bi-iodate solution, 0.0021M (0.0126N), Dissolve 812.4 mg KH(I03)2 in
distilled water and dilute to 1000 mL .
g. Standardisation: Take 100 to 150 mL distilled water in an Erlenmeyer flask. Add
approximately 2g KI, dissolve. Add 1 mL 6N H2S04 or a few drops of conc H2SO4 and 20 mL
bi-iodate solution. Dilute to 200 mL and titrate liberated iodine with thiosulphate titrant to a
pale straw colour. Add a few drops of starch indicator. Continue titration to first disappearance
of blue colour. Calculate molarity, M of thiosulphate as:
where: V = mL of thiosulphate used
Procedure
a. Drain any liquid in the flared lip of the BOD bottle containing the sample.
V
0.02520
M
×
=

b. Remove stopper and add 1 mL of MnSO4 followed by 1 mL alkali-iodide-azide reagent. Hold
the pipette tip just below the liquid surface touching the side of the bottle. Wash the pipette
before returning to the reagent bottles.
c. Stopper carefully to exclude air bubbles. Mix by inverting the bottle a few times.
d. Allow the brown manganese hydroxide floc (white floc indicates absence of DO) to settle
approximately to half the bottle volume, add 1.0 mL conc H2SO4 and re-stopper. Mix by
inverting several times until dissolution is complete.
e. Titrate 201 mL sample with standard Na2S2O3 as for standardisation procedure described
above.
Calculation
where: V = mL thiosulphate solution used
M = molarity of thiosulphate titrant
Reporting
Report dissolved oxygen in units of mg/L with 1 digit after the decimal point, e.g. 8.2 mg/L.
0.025
MV
DO/Lmg
×
=

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